Port Monitor Administrative File _pmtab (ONC+ Developer's Guide)

ONC+ Developer's Guide

Port Monitor Administrative File `_pmtab`

Each port monitor has two directories for its exclusive use. The current directory contains files defined by the SAF (_pmtab, _pid) and the per-service configuration scripts, if they exist. The directory /var/saf/pmtag, where pmtag is the tag of the port monitor, is available for the port monitor's private files.

Each port monitor has its own administrative file. Use the pmadm command to add, remove, or modify service entries in this file. Each time a change is made using pmadm, the corresponding port monitor rereads its administrative file. Each entry in a port monitor's administrative file defines how the port monitor treats a specific port and what service is to be invoked on that port.

Some fields must be present for all types of port monitors. Each entry must include a service tag to identify the service uniquely and an identity to be assigned to the service when it is started, for example, root.

The combination of a service tag and a port monitor tag uniquely define an instance of a service. You can use the same service tag to identify a service under a different port monitor. The record must also contain port monitor-specific data (for example, for a ttymon port monitor, this data includes the prompt string which is meaningful to ttymon). Each type of port monitor must provide a command that takes the necessary port monitor-specific data as arguments and outputs this data in a form suitable for storage in the file. The ttyadm command provides the formatting for ttymon, nlsadmin for listen. For a user-defined port monitor, you also must supply a similar administrative command.

Each service entry in the port monitor administrative file must have the following format and contain the following information:

svctag:flgs:id:reserved:reserved:reserved:pmspecific# comment

SVCTAG is a unique tag that identifies a service. This tag is unique only for the port monitor through which the service is available. Other port monitors can offer the same or other services with the same tag. A service requires both a port monitor tag and a service tag to identify it uniquely.

SVCTAG may consist of up to 14 alphanumeric characters. The service entries are defined in the following table.

Table F–2 SVCTAG Service Entries


Service Entries	Description
`FLGS`	Flags with the following meanings might currently be included in this field: `-x` Do not enable this port. By default, the port is enabled. `-u` Create a `utmpx` entry for this service. By default, no `utmpx` entry is created for the service.
`ID`	The identity under which the service is to be started. The identity has the form of a login name as it appears in `/etc/passwd`.
`PMSPECIFIC`	Examples of port monitor information are addresses, the name of a process to execute, or the name of a `STREAMS` pipe through which to pass a connection. This information varies to meet the needs of each different type of port monitor.
`COMMENT`	A comment associated with the service entry.

Note –

Port monitors might ignore the -u flag if creating a utmpx entry for the service is not appropriate to the manner in which the service is to be invoked. Some services might not start properly unless utmpx entries have been created for them, for example, login.

Each port monitor administrative file must contain one special comment of the form:

# VERSION=value

In this case, value is an integer that represents the port monitor's version number. The version number defines the format of the port monitor administrative file. This comment line is created automatically when a port monitor is added to the system. It appears on a line by itself, before the service entries.